Effect of cotransfection of the PP/Gla domain on secretion of PZ and FX. Ten micrograms of each PP-Gla construct were cotransfected with 2 μg pcDNA-PZ^MetLuc (A) or -FX^MetLuc (B). Twenty-four hours after incubation with warfarin (W, □) or Vit.K (K, ■), MetLuc activity in the medium (top panel) and barium citrate-adsorbate (bottom panel) were measured. Values of means (± SD) for 3 transfections were calculated relative to the activity of cotransfected samples by empty pcDNA treated with Vit.K (arbitrarily set at 100%; *P < .05; **P < .005; ***P < .001).